Many conventional loudspeakers produce sound by inducing piston-like motion in a diaphragm. Panel audio loudspeakers, such as distributed mode loudspeakers (DMLs), in contrast, operate by inducing uniformly distributed vibration modes in a panel through an electro-acoustic actuator. Typically, the actuators are electromagnetic or piezoelectric actuators.
Conventional piezoelectric actuators often include toxic materials such as lead, while conventional EM actuators can include, pre-magnetized materials such as iron or neodymium, which can be heavy, brittle, and/or difficult to manufacture. In addition, pre-magnetized materials may become inoperable when heated above their Curie temperatures, therefore causing a conventional piezoelectric actuator that includes the pre-magnetized materials to stop operating.